1. Field of the Invention
The present invention relates generally to lacrosse sticks, and more particularly, to lacrosse stick heads having a skeletal member made of a first material, over which an outer skin made of a second material is applied.
2. Background of the Invention
In 1970, the introduction of double-wall, synthetic lacrosse heads revolutionized the game of lacrosse. In comparison to the traditional wooden single-wall heads, the synthetic heads imparted a balance, lightness, maneuverability, and flexibility never-before experienced by lacrosse players. These performance advantages greatly enhanced players' skills such as throwing, catching, cradling, and scooping, and brought the sport of lacrosse to new levels of speed and excitement.
FIG. 1 illustrates a conventional lacrosse stick 100 having a handle 102 shown in dotted lines and a double-wall synthetic head 104. Head 104 includes a generally V-shaped frame having a juncture 106, sidewalls 108 and 110, a transverse wall (or “scoop”) 112 joining the sidewalls at their ends opposite juncture 106, and a stop member 114 joining sidewalls 108 and 110 at their ends nearest juncture 106. As shown, handle 102 fits into and through juncture 106, and abuts stop member 114. A screw or other fastener placed through opening 107 secures handle 102 to head 104.
For traditionally-strung pockets (which have thongs and string instead of mesh), thongs (not shown) made of leather or synthetic material extend from upper thong holes 116 in scoop 112 to lower thong holes 118 in stop member 114. In some designs, such as the design shown in FIG. 1, upper thong holes 116 are located on tabs 117 of the scoop 112. On other designs, upper thong holes 116 are located directly on the scoop 112. FIG. 1 shows four pairs (116, 118) of thong holes that accept four thongs. To complete the pocket web, the thongs have nylon strings threaded around the thongs and string laced through string holes 120 in sidewalls 108 and 110, forming any number of diamonds (crosslacing). Finally, one or more throwing or shooting strings extend transversely between the upper portions of sidewalls 108 and 110, attaching to throwing string hole 124 and a string laced through string hole 122. The typical features of a lacrosse stick are shown generally in Tucker et al., U.S. Pat. No. 3,507,495, Crawford et al., U.S. Pat. No. 4,034,984, and Tucker et al., U.S. Pat. No. 5,566,947, which are all incorporated by reference herein.
In addition to traditionally-strung heads, some heads use mesh pockets or a combination of traditional and mesh stringing. In any case, the mesh or stringing is conventionally attached to the head through holes in the scoop, sidewalls, and stop members, or by tabs attached to the scoop, sidewalls, and stop members. These tabs can have openings through which mesh or stringing is threaded, or can be shaped (e.g., like a hook) to retain loops of the mesh or stringing.
As used herein, thread holes or thread openings refer to the openings that receive the various forms of pocket stringing, such as the holes in the scoop, sidewalls, and stop members, or the openings in tabs attached to the scoop, sidewalls, and stop members. The term “openings” should be construed broadly so as to encompass any hole or structure that retains the pocket stringing, including structures such as hooks. Also, as used herein, a pocket thread refers to any member, such as a thong, string, or mesh, that forms the pocket and/or attaches the pocket to the lacrosse head.
The traditional double-wall synthetic head is an injection-molded, monolithic structure. Examples of suitable synthetic materials well known in the art include nylon, urethane, and polycarbonate. When first introduced, these materials were clearly superior to wood, offering players improved handling and durability. For example, a lacrosse head constructed of DuPont™ ZYTEL ST 801 nylon resin is able to withstand the bending and harsh impacts inherent to competition far better than a traditional wooden stick. As another example, polycarbonate, though having a flexibility similar to wood, is more structurally durable than wood and much lighter and, therefore, easier to handle.
Although the synthetic materials can afford significant performance advantages, the use of a single material in a monolithic head limits a manufacturer's ability to satisfy divergent performance characteristics. For example, to provide better ball control during face-offs or when scooping ground balls, a player may prefer a strong but deformable lacrosse head that returns to its original shape once the deforming force is removed. At the same time, a player may desire a less rigid, compressible, vibration-dampening lacrosse head that absorbs impacts to the lacrosse head by other sticks to help prevent a ball from being jarred from the head. With a monolithic head, the manufacturer must choose a material that serves both of these disparate purposes. Although the manufacturer can compensate somewhat for this performance tradeoff by using structural elements (e.g., increasing the thickness of the sidewalls), the practical result of the tradeoff is a lacrosse head that satisfies neither purpose optimally.
There are many other examples of these types of tradeoffs in choosing a material for a monolithic lacrosse head. For example, providing the necessary rigidity in a monolithic lacrosse head can compromise the ability to provide a dampening pocket. In an effort to deepen a pocket as much as possible, some conventional men's lacrosse heads maximize the height of the sidewalls to the upper limit of 2 inches that is mandated by applicable rules. Coupled with the maximum allowed 2½-inch pocket (the diameter of a lacrosse ball), this sidewall height provides the lacrosse head with the maximum allowed total depth of 4½ inches. Unfortunately, maximizing the height of the traditional monolithic rigid sidewall does not enhance the flexibility of the pocket in any way. The rigid frame of the traditional lacrosse head can make the overall catching area stiff and unforgiving. Indeed, the only non-rigid component of the conventional men's lacrosse head is the 2½ inches of pocket. A sharp jolt to the stick, as often happens when a player is checked, can cause the stiff frame to jerk the pocket and propel the ball out of the lacrosse head. Players would therefore prefer a less rigid lacrosse head that better dampens the pocket to keep a ball in the lacrosse head.
Another significant tradeoff pertains to the hardness of the lacrosse head. To provide the rigidity necessary to handle and protect the heavy, hard rubber ball, and to provide the durability necessary to endure the severe impacts of the game, synthetic materials must possess a substantial degree of stiffness, strength, and abrasion resistance. A drawback to these characteristics is the frequent injuries inflicted upon other lacrosse players by impact with the hard lacrosse head. Often, players have their fingers crushed between the lacrosse head of an opponent and the lacrosse stick handle that they are holding. In addition, throwing and checking with the lacrosse sticks regularly result in inadvertent or deliberate contact with players' faces, arms, and other body parts. This injury problem is a particular concern for the women's game, in which the players wear virtually no personal protective equipment (e.g., no helmets or padding), yet the lacrosse heads are made of the same materials used in the men's heads. Further, in the women's game, despite game rules designed to avoid stick contact with the body, inadvertent contact with body parts regularly occurs.
On a larger scale, this injury problem is detrimental to the sport's popularity, as many young players are discouraged by the pain of routine contact. To reduce injuries, manufacturers could choose a softer lacrosse head material. However, a lacrosse head with a significantly lower flex modulus leads to excessive flexing, poor recovery from flexing, and inadequate rigidity for ball handling and legal checking purposes.
In an effort to soften the hard monolithic heads, some designs, such as that disclosed in British Patent No. 424,742 to Muir, attach soft materials using adhesives to a hard lacrosse head frame. Muir attaches a rubber sheath to a traditional wood frame. As observed in a cross-sectional view, the sheath represents only a very small portion of the cross-sectional area of the Muir head, with the overwhelming area attributable to the wood frame.
Another example of a performance tradeoff concerns the rigidity of the lacrosse head frame in relation to the tightness of the pocket strings. With conventional monolithic lacrosse heads, the stiffer the material of the head, the less the head flexes or “gives” in response to tension on the pocket. As a result, the pocket in a women's lacrosse head can become excessively tight, such that impact with the ball causes a trampoline effect that makes the ball hard to catch and control. In essence, the pocket, strung on a rigid unforgiving frame, acts like the strings of a tennis racquet and rebounds the ball out of the pocket. This trampoline effect is especially troublesome for women's lacrosse sticks, which have shallower and more tightly strung pockets than men's lacrosse sticks. (According to United States lacrosse rules, the combined height of the sidewall and pocket of women's lacrosse stick cannot exceed 2½ inches, while the men's can be up to 4½ inches, in effect allowing a standard 2½ inch ball to sag 2 inches below the men's sidewall.) Again, restricted to a monolithic head, a manufacturer could use a more energy absorbing material to reduce the trampoline effect. However, using a more energy absorbing material can make the head less rigid and less suitable for accurate passing and shooting, and for protecting against ball-jarring hits.
Another example of a tradeoff in performance characteristics relates to areas of a lacrosse head that must satisfy needs significantly different from the principal concerns of rigidity and flexibility. For example, manufacturers typically add a separate ball stop to the stop area of a lacrosse head to help deaden incoming balls. Conventionally, this piece is made of highly compressible, energy-absorbing material, e.g., foam. This foam ball stop is typically applied to the lacrosse head with adhesive and serves to absorb the ball's impact with the hard lacrosse head and thereby improve ball control. With monolithic lacrosse heads, constructing the entire head of this foam is completely impractical because of its lack of strength and rigidity. Thus, due to the playing characteristics expected of a modern lacrosse head, manufacturers have been unable to produce a lacrosse head with a shock absorbing stop area without adding a separate ball stop.
In addition to injection-molded synthetic lacrosse heads, some lacrosse stick designers have experimented with composite materials to form a lacrosse head, an example of which is described in U.S. Pat. No. 5,685,791 to Feeney. The composite lacrosse stick head of Feeney comprises a tube with a generally oval-shaped cross section with a length shaped into a closed loop head. The tube is fabricated of elongated fibers in a parallel configuration. The fibers are applied in layers and are set in an elastomeric binder material. Notably, the composite lacrosse stick head of Feeney is hollow and includes the composite tube as its only structure. The pocket is strung to holes or apertures in the composite tube, which are preferably drilled in the head during a secondary operation.
In shaping the tube, a thin air bladder is placed inside the wound strips of composite material. After the windings are bent to the intended configuration corresponding to the lacrosse stick head, the windings are placed in a mold. The bladder is then inflated to keep the windings in contact with the mold for shaping during curing. Alternatively, instead of air, the bladder can be filled with a foam material that expands when heated and provides the necessary forming pressure during the cure cycle. Importantly, however, because this foam is inside of the tube, it cannot provide any flexibility to the lacrosse head and does not structurally support the head. Instead, only the composite tube provides structural support and any inherent flexibility it may have.
Thus, in view of the drawbacks of conventional injection-molded monolithic heads and composite heads, there remains a need for a lacrosse head that better satisfies the divergent performance requirements discussed above. In particular, there remains a need for a lacrosse head that possesses the necessary structural support while also satisfying preferences for pocket dampening, ball control, protective cushioning, and light weight.